Hi B.! I am so sorry that your family is going through this. My 4 year old daughter and 7 year old son both have Type 1 diabetes, as does my husband.
You won't qualify for SSI, but you may be able to contact your insurance company to see if they have grants that will cover part of your premium.
As far as going back to work, only you know what is best for your son. People don't realize how serious Type 1 can be, and how ignorant the general medical community is about the disease. But there are ways that you can return to work.
#1. Your school should have the number of your pediatric endocrinologist, and the nurse would be able to call that number and get advice on how to handle blood sugars, lows, etc.
#2. Make a support team. We are training my parents how to deal with the detailed care. Most things can be handled over the phone, now. We also have 2 close friends who we will be training to insert an insulin pump site. The more people you have on your "team" that you can trust, the better. My MIL and my sisters are also a good resource for us. We can leave town for the day and know that our kids will be safe!
JDRF is a great resource for support groups and you can meet other families dealing with the disease through Walk for the Cure and other events.
Lastly, no one can tell you that things will "get back to normal". There is no normal with type 1 diabetes. There are phases of ups and downs, and you learn to roll with it, but it's still a very difficult disease to manage, especially for growing kids. You just have to find a new normal and do what works for you.
My heart goes out to you. My daughter was diagnosed at age 19 months and I don't think I've had a good night's sleep since. We have great days and horrible days and absolutely terrifying days. Our kids will have a wonderfully normal life, but parents have to take up the slack to make that happen.
Cheers to our kids! Type 1 won't hold them back! My husband may have type 1 but he's super healthy, is a successful business owner and an athlete. A family friend has 2 kids with diabetes and those kids are state tennis champions and never let diabetes define them or hold them back.
Blessings on you and your family!